Ebay Car Sales, why are reserve's secret?

[Shortsguy1]

I apologize if this isn't the right subforum to post this in, but hopefully someone would be willing to explain a few things about buying (and selling) Mercedes cars to a relative newcomer.

1) Do cars sold on ebay generally sell for more than on craigslist? I see the same cars bounce back and forth between the two sites, and I wonder if one is generally gets a higher price. (I am looking at this from a buyer's perspective).

2) Why are reserves kept hidden? It seems to me that it wastes a lot of people's time by keeping them secret.

3) Based on your experiences, do reserves increase or decrease the final selling price of a car? I guess there is no way to know for sure, but what are your thoughts?

Right now, (at least) two of our members have cars on ebay and one is using a reserve (and won't specify the amount when asked) and the other has no reserve. I am just trying to understand the consequences of each decision. I personally am less likely to bid on an item with a reserve, but maybe others react differently.